1. Short introduction of the target region

Třebíč is a city situated in the west Moravia, in the south-eastern part of the Vysočina Region. Average altitude is about 406 m above sea. Třebíč has about 39000 inhabitants. It is an important centre of western Moravia. Třebíč area is 56 km2 and the city is divided into 17 parts, of which 10 are located in urban areas and the remaining 7 in the vicinity.

Figure 1 Map of Czech Republic

Figure 2 View of the city Třebíč

In Třebíč is created central heating system (CHS). It consists of 3 main branches (north, south and west). Each of them has undergone in the past 10 years, a gradual process of removing local resources and connection to the CHS. CHS uses biomass as main fuel. The share of biomass gradually grew to now about 90% (in 2010).

Development of the population has a slightly downward trend.

Agricultural production and forestry

For Třebíč is characterized a high percentage of arable land (87,4%) and low percentage of grass over (10%). They are found also vineyards of the area of 3 hectares. Agriculture sector is largely determined by natural and soil conditions.

Graph 2 Structure of agricultural lad in Třebíč compared with the Czech Republic

2. Characteristic of energy demand

Climatic conditions are the first factor that affects heat loss and thus the heat consumption for heating. Czech Republic is relatively small, but there exist some differences in the climatic conditions. They are mainly caused by varying altitude, the air flow characteristics and differences in the sunshine.
The external temperature is, unlike the internal temperature, very variable. For design of heating for buildings it is used, the so-called "outdoor calculated temperature" which is derived from long-term averages of the five coldest days. For the purpose of calculating heat loss and heat demand for heating is the CR divided into four temperature zones with a fixed "computational temperature" of -12, -15, -18, -21 ° C.

Table 2 Summary of information for determining the outdoor calculated temperature

Table 3 Climatic value in 2009

For evaluating the need for a new heating source is necessary to know the requirements for the individual needs of the population.

Average annual consumption of population in Třebíč is about 36 GJ per apartment 3+1 (average area 72 m²). This requirement represents a consumption of about 3 tons of straw of 10 tons of wood chips.

Currently is to the existing system connected 9800 flats, with an average of 2,5 inhabitant per flat it is about 24500 inhabitants of total 39000 inhabitants of town Třebíč.

Table 4 The annual consumption of biomass in CHS (data for 2010)

3. Availability of energy sources

From the perspective of the role of determining the potential of biomass energy to be primarily distinguished by origin of biomass (forest mining residues, wood chips from plantations of fast growing trees (RRD), straw, energy herbs, etc.). Various forms of biomass have different properties to determine (or limiting) their use, and various costs for their acquisition.

Another factor that influences the choice of biomass forms is the fact, which different forms of biomass have with respect to their use of different features (different energy technologies for electricity, heat). It is necessary to evaluate, if for the technology will be used only local sources (e.g. permanent grassland) or will be biomass transported from a bigger distance (e.g. chips from RRD). In this case, play a significant role economy provision of biomass, including transport costs.

Figure 3 Straw yields of conventional farming crops

For energy use is a potential about 20000 hectares of forest. Of this area approximately 16000 hectares own Forests of the Czech Republic in other areas are owners – municipalities or private owners. The potential of the green chips in region is about 8000 t. For large-scale chipping are suitable only clear-cutting (brushwood).


Figure 4 Example of waste biomass (firewood) stored in the forest before further use

The source of fuel are local, the largest share of supply is obtained by chipping of waste wood from local forests. A significant source of wood chips are also pruning the local and surrounding urban parks. In available potential areas to 40 km from Třebíč is 32 000 t of biomass. This is the green chips, sawdust and bark.

This represents with the calorific value of 8 GJ / t and efficiency of 85% about 217 600 GJ of heat. If will be the lack of suitable fuel in the future, there is a possibility, to create plantations of fast growing species which would then be able to meet the required demand for fuels. At the based on the obtain information it can be stated that in the district Třebíč (and nearest surrounds) is the sufficient potential of straw, waste biomass and wood for the used
technology.

4. Proposed actions/programs/projects

In Třebíč is created central heating system (CHS). It consists of 3 main branches (north, south and west). Each of them has undergone in the past 10 years, a gradual process of removing local resources and connection to the CHS. CHS uses biomass as main fuel. The share of biomass gradually grew to now about 90% (in 2010).

The basic question for strategy development is, is it better to continue in expansion of district heating or support modernization of local heating sources.

Centralized heat source has with comparison of local heating over number advantages.

Given the current status of connection the main part of the city to a centralized system is environmentally and economically preferable to continue in its expansion.

The main advantage of central heating is the elimination of emissions from a large number of small boiler in houses.

Besides the huge reduction of CO₂ central heating system represent also easy and convenient choice for end users because they reduce demand for operation of the heating device and their energy costs are low and stable.

Due to supply of domestic and foreign producers in this field, are evaluated the investment cost, but also the operational characteristics and availability of equipment, availability of service, etc.

Most producers are able to supply their equipment in various power ranges. All systems are fully automated (without service) from fuel intake to exhaust combustion gases and ash transport.

The various devices differ in measurement systems, and control combustion process. These differences are always in accordance with established standards and regulations. Price differences for these systems are not significant, differences was about 10% (compared to each other).

Many facilities are universal and can burn various forms of biomass, in these cases, however, increased demand for fuel pre-treatment. The device, in which is exactly assess requirement for the fuel, have no other additional requirements for the fuel pre-treatment. With compared with universal device, that has higher requirements for fuel pre-treatment and facilities with strict requirements on the fuel properties, of the boilers were universal in some cases about 20% cheaper (on average was saving about 13%). To this item has been counted the costs associated with increased requirements for storage of this fuel (for saving required quality of fuel). At the base of this information was for other selection included only universal boilers (this choice was also made according to different types of biomass, which is located in the area).

With comparison of investment cost for the boiler was the boilers of foreign producers expansive on average in 12%.

From the Czech producers of boilers can be recommended the products of company TTS eko and company Step Trutnov.

From company TTS eco was advised boiler VESKO-B (burned wood material), VESKO-S (burned straw bales) and from the company Step Trutnov boiler burned straw bales.

 

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